摘要
pH和氧气是古菌氨氧化活性的关键限制因子。然而,复杂土壤中不同古菌生态型(土壤古菌和海洋古菌)对pH和氧气的竞争适应规律尚未有相关报道。选择活性氨氧化古菌(ammonia-oxidizing archaea,AOA)为类海洋古菌Group1.1a-associated的酸性森林土(pH5.40)和活性氨氧化古菌为土壤类古菌Group 1.1b的碱性水稻土(pH8.02),调节混合土壤pH和氧气浓度;设置稳定性同位素核酸探针实验,通过微宇宙室内培养,监测土壤硝化强度;利用实时荧光定量qPCR和454高通量测序研究pH和氧气对土壤氨氧化古菌和细菌的影响规律。结果表明:pH3.8下没有硝化作用发生,而pH6.0和7.6则发生了强烈硝化作用,且高氧环境下硝化作用强于低氧环境;加底物培养后,氨氧化古菌数量明显增加;活性氨氧化古菌几乎全为土壤类古菌Group 1.1b。研究表明:尽管氧气对硝化作用也有一定影响,但pH是影响硝化作用的主要因素;与类海洋古菌相比,土壤类古菌Group 1.1b更能适应高氧和低氧的碱性土壤环境,因此具有更强的竞争力。
【Objective】pH and oxygen were the key limiting factors for the ammonia oxidation activity of archaea.The law of competition and adaptation of different archaea ecotypes(soil archaea and marine archaea)to pH and oxygen in complex soils are still unclear.【Method】Ammonia-oxidizing archaea(AOA)was selected as the marine archaea Group1.1a-associated with acid forest soil with pH=5.40,and the active ammonia-oxidizing archaea were selected as the soil archaea Group 1.1b-associated with alkaline paddy soil with pH=8.02.After adjusting the pH and oxygen concentration of the mixed soil,a stable isotopic probe microcosm indoor culture experiment was set up to analyze the intensity of soil nitrification.Also,quantitative PCR and 454 high-throughput sequencings were employed to study the effect of different pH and oxygen conditions on the number of soil ammonia-oxidizing archaea and bacteria and also the types of active ammonia-oxidizing microorganisms present.【Result】Compared with zero time,the contents of nitrate nitrogen and ammonium nitrogen had no change at pH3.8;At pH6.0 and 7.6,nitrate nitrogen content increased by 23 times and 19 times,respectively,and the ammonium nitrogen content decreased significantly.The results show that after the soil samples were mixed,there was no nitrification at pH 3.8,while strong nitrification occurred at pH 6.0 and 7.6.Also,the nitrification in a high-oxygen environment was stronger than that in a low-oxygen environment.After substrate culture,the number of oxidizing archaea was increased significantly;DNA-SIP shows that the active ammonia oxidizing archaea with pH 6.0 and 7.6 were almost all soil archaea Group 1.1b.【Conclusion】This study reveals that pH rather than oxygen is the main factor affecting nitrification.Although oxygen also has a certain effect on nitrification;in neutral and alkaline soil,soil archaea lineage has greater activity in high O_(2) and low O_(2) environment and have more adaptive capacity than marine lineage.
作者
熊旭梅
周雪
郭佳
贾仲君
蒋先军
XIONG Xumei;ZHOU Xue;GUO Jia;JIA Zhongjun;JIANG Xianjun(College of Resources and Environment,Southwest University,Chongqing 400715,China;College of Agricultural Science and Engineering,Hohai University,Nanjing 210098,China;State Key Laboratory of Soil and Sustainable Agriculture,Nanjing Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China)
出处
《土壤学报》
CAS
CSCD
北大核心
2022年第3期833-843,共11页
Acta Pedologica Sinica
基金
国家自然科学基金重点项目(41530857)资助。